The invention in general relates to the recognition of patterns such as embodied in a collection of digital signals. Known objects for such recognition are binarized characters (letters, digits), blood corpuses, chromosomes, radar images of aeroplanes. Other visible patterns in this respect are series of code digits, mutilated or not, human voice patterns, and so on. The invention notably concerns a device for recognizing a pattern of a predetermined number of separate digital signals which are arranged according to at least one coordinate and each of which has a signal value, the device comprising an input with first storage means for receiving and storing said pattern, second storage means with a predetermined number of storage locations, each of which has a storage capacity for a corresponding pattern, a difference determining device with a first input which is connected to a data output of the first storage means, a second input which is connected to a data output of the second storage means, and an output for alternatively supplying a non-correspondence/correspondence signal.
The coordinates may be the x-direction and the y-direction in the case of a two-dimensional image, the time in the case of a series of code bits received, and the time and the pitch in the case of a voice pattern. The number of coordinates may be 1, 2, 3 or even more. The signal value may concern the density or colour code in the case of two-dimensional images, the intensity of the sound in the case of a voice pattern, etc. The recognition of unknown patterns has since long received attention and forms the subject of many articles and Patent Specifications. The following description relates notably to the recognition of two-dimensional, static images. However, as has already been stated, the invention can also be used for other patterns. The invention is based on the idea that many patterns are a combination of components which are already significant themselves. For example, medical X-ray images may contain a number of details such as parts of a skeleton. Other images contain, for example, individual chromosomes or blood corpuscles which are to be counted and/or identified.